Iguanodectes adujai is a small tetra with a slender build, reaching a maximum of 6.2 cm (2.4 in) standard length (SL).

[2][3][4] I. adujai specifically has pale-silver scales, a yellowish underside, and a red lateral stripe that ends in a blotch of pigmentation at the caudal fin.

"Iguanodectes" comes from "iguana", the lizard, and "dectes", meaning "bite" or "tooth"; though it was not made clear in the original text, it is assumed that this is in reference to the "lizard-like" dentition.

[16] Its type locality speaks to a preference for blackwater habitats, which are characterized by plentiful riparian vegetation and a substrate largely composed of leaf litter.

[17] The Rio Negro basin is well-known for its floodplains, including an area in which the Itu is located,[18] and associated flooding cycles may have an influence on I. adujai's diet and behavior.

[4] It seems to be a fairly opportunistic feeder, including crustaceans, insects, algae, fallen fruit, and leaf litter in its diet.

[23] Nonetheless, freshwater aquatic habitats - especially wetlands - in South America are frequently under pressure from various ongoing anthropogenic hazards, including illegal mining and infrastructure development.

[24] Iguanodectes adujai is exported from its native habitat to various locations, including Germany and Poland, on an uncommon basis.